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bb4ce825 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
f606a88e OM |
2 | /* |
3 | * The AEGIS-256 Authenticated-Encryption Algorithm | |
4 | * | |
5 | * Copyright (c) 2017-2018 Ondrej Mosnacek <omosnacek@gmail.com> | |
6 | * Copyright (C) 2017-2018 Red Hat, Inc. All rights reserved. | |
f606a88e OM |
7 | */ |
8 | ||
9 | #include <crypto/algapi.h> | |
10 | #include <crypto/internal/aead.h> | |
11 | #include <crypto/internal/skcipher.h> | |
12 | #include <crypto/scatterwalk.h> | |
13 | #include <linux/err.h> | |
14 | #include <linux/init.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/scatterlist.h> | |
18 | ||
19 | #include "aegis.h" | |
20 | ||
21 | #define AEGIS256_NONCE_SIZE 32 | |
22 | #define AEGIS256_STATE_BLOCKS 6 | |
23 | #define AEGIS256_KEY_SIZE 32 | |
24 | #define AEGIS256_MIN_AUTH_SIZE 8 | |
25 | #define AEGIS256_MAX_AUTH_SIZE 16 | |
26 | ||
27 | struct aegis_state { | |
28 | union aegis_block blocks[AEGIS256_STATE_BLOCKS]; | |
29 | }; | |
30 | ||
31 | struct aegis_ctx { | |
32 | union aegis_block key[AEGIS256_KEY_SIZE / AEGIS_BLOCK_SIZE]; | |
33 | }; | |
34 | ||
35 | struct aegis256_ops { | |
36 | int (*skcipher_walk_init)(struct skcipher_walk *walk, | |
37 | struct aead_request *req, bool atomic); | |
38 | ||
39 | void (*crypt_chunk)(struct aegis_state *state, u8 *dst, | |
40 | const u8 *src, unsigned int size); | |
41 | }; | |
42 | ||
43 | static void crypto_aegis256_update(struct aegis_state *state) | |
44 | { | |
45 | union aegis_block tmp; | |
46 | unsigned int i; | |
47 | ||
48 | tmp = state->blocks[AEGIS256_STATE_BLOCKS - 1]; | |
49 | for (i = AEGIS256_STATE_BLOCKS - 1; i > 0; i--) | |
50 | crypto_aegis_aesenc(&state->blocks[i], &state->blocks[i - 1], | |
51 | &state->blocks[i]); | |
52 | crypto_aegis_aesenc(&state->blocks[0], &tmp, &state->blocks[0]); | |
53 | } | |
54 | ||
55 | static void crypto_aegis256_update_a(struct aegis_state *state, | |
56 | const union aegis_block *msg) | |
57 | { | |
58 | crypto_aegis256_update(state); | |
59 | crypto_aegis_block_xor(&state->blocks[0], msg); | |
60 | } | |
61 | ||
62 | static void crypto_aegis256_update_u(struct aegis_state *state, const void *msg) | |
63 | { | |
64 | crypto_aegis256_update(state); | |
65 | crypto_xor(state->blocks[0].bytes, msg, AEGIS_BLOCK_SIZE); | |
66 | } | |
67 | ||
68 | static void crypto_aegis256_init(struct aegis_state *state, | |
69 | const union aegis_block *key, | |
70 | const u8 *iv) | |
71 | { | |
72 | union aegis_block key_iv[2]; | |
73 | unsigned int i; | |
74 | ||
75 | key_iv[0] = key[0]; | |
76 | key_iv[1] = key[1]; | |
77 | crypto_xor(key_iv[0].bytes, iv + 0 * AEGIS_BLOCK_SIZE, | |
78 | AEGIS_BLOCK_SIZE); | |
79 | crypto_xor(key_iv[1].bytes, iv + 1 * AEGIS_BLOCK_SIZE, | |
80 | AEGIS_BLOCK_SIZE); | |
81 | ||
82 | state->blocks[0] = key_iv[0]; | |
83 | state->blocks[1] = key_iv[1]; | |
84 | state->blocks[2] = crypto_aegis_const[1]; | |
85 | state->blocks[3] = crypto_aegis_const[0]; | |
86 | state->blocks[4] = key[0]; | |
87 | state->blocks[5] = key[1]; | |
88 | ||
89 | crypto_aegis_block_xor(&state->blocks[4], &crypto_aegis_const[0]); | |
90 | crypto_aegis_block_xor(&state->blocks[5], &crypto_aegis_const[1]); | |
91 | ||
92 | for (i = 0; i < 4; i++) { | |
93 | crypto_aegis256_update_a(state, &key[0]); | |
94 | crypto_aegis256_update_a(state, &key[1]); | |
95 | crypto_aegis256_update_a(state, &key_iv[0]); | |
96 | crypto_aegis256_update_a(state, &key_iv[1]); | |
97 | } | |
98 | } | |
99 | ||
100 | static void crypto_aegis256_ad(struct aegis_state *state, | |
101 | const u8 *src, unsigned int size) | |
102 | { | |
103 | if (AEGIS_ALIGNED(src)) { | |
104 | const union aegis_block *src_blk = | |
105 | (const union aegis_block *)src; | |
106 | ||
107 | while (size >= AEGIS_BLOCK_SIZE) { | |
108 | crypto_aegis256_update_a(state, src_blk); | |
109 | ||
110 | size -= AEGIS_BLOCK_SIZE; | |
111 | src_blk++; | |
112 | } | |
113 | } else { | |
114 | while (size >= AEGIS_BLOCK_SIZE) { | |
115 | crypto_aegis256_update_u(state, src); | |
116 | ||
117 | size -= AEGIS_BLOCK_SIZE; | |
118 | src += AEGIS_BLOCK_SIZE; | |
119 | } | |
120 | } | |
121 | } | |
122 | ||
123 | static void crypto_aegis256_encrypt_chunk(struct aegis_state *state, u8 *dst, | |
124 | const u8 *src, unsigned int size) | |
125 | { | |
126 | union aegis_block tmp; | |
127 | ||
128 | if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) { | |
129 | while (size >= AEGIS_BLOCK_SIZE) { | |
130 | union aegis_block *dst_blk = | |
131 | (union aegis_block *)dst; | |
132 | const union aegis_block *src_blk = | |
133 | (const union aegis_block *)src; | |
134 | ||
135 | tmp = state->blocks[2]; | |
136 | crypto_aegis_block_and(&tmp, &state->blocks[3]); | |
137 | crypto_aegis_block_xor(&tmp, &state->blocks[5]); | |
138 | crypto_aegis_block_xor(&tmp, &state->blocks[4]); | |
139 | crypto_aegis_block_xor(&tmp, &state->blocks[1]); | |
140 | crypto_aegis_block_xor(&tmp, src_blk); | |
141 | ||
142 | crypto_aegis256_update_a(state, src_blk); | |
143 | ||
144 | *dst_blk = tmp; | |
145 | ||
146 | size -= AEGIS_BLOCK_SIZE; | |
147 | src += AEGIS_BLOCK_SIZE; | |
148 | dst += AEGIS_BLOCK_SIZE; | |
149 | } | |
150 | } else { | |
151 | while (size >= AEGIS_BLOCK_SIZE) { | |
152 | tmp = state->blocks[2]; | |
153 | crypto_aegis_block_and(&tmp, &state->blocks[3]); | |
154 | crypto_aegis_block_xor(&tmp, &state->blocks[5]); | |
155 | crypto_aegis_block_xor(&tmp, &state->blocks[4]); | |
156 | crypto_aegis_block_xor(&tmp, &state->blocks[1]); | |
157 | crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE); | |
158 | ||
159 | crypto_aegis256_update_u(state, src); | |
160 | ||
161 | memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE); | |
162 | ||
163 | size -= AEGIS_BLOCK_SIZE; | |
164 | src += AEGIS_BLOCK_SIZE; | |
165 | dst += AEGIS_BLOCK_SIZE; | |
166 | } | |
167 | } | |
168 | ||
169 | if (size > 0) { | |
170 | union aegis_block msg = {}; | |
171 | memcpy(msg.bytes, src, size); | |
172 | ||
173 | tmp = state->blocks[2]; | |
174 | crypto_aegis_block_and(&tmp, &state->blocks[3]); | |
175 | crypto_aegis_block_xor(&tmp, &state->blocks[5]); | |
176 | crypto_aegis_block_xor(&tmp, &state->blocks[4]); | |
177 | crypto_aegis_block_xor(&tmp, &state->blocks[1]); | |
178 | ||
179 | crypto_aegis256_update_a(state, &msg); | |
180 | ||
181 | crypto_aegis_block_xor(&msg, &tmp); | |
182 | ||
183 | memcpy(dst, msg.bytes, size); | |
184 | } | |
185 | } | |
186 | ||
187 | static void crypto_aegis256_decrypt_chunk(struct aegis_state *state, u8 *dst, | |
188 | const u8 *src, unsigned int size) | |
189 | { | |
190 | union aegis_block tmp; | |
191 | ||
192 | if (AEGIS_ALIGNED(src) && AEGIS_ALIGNED(dst)) { | |
193 | while (size >= AEGIS_BLOCK_SIZE) { | |
194 | union aegis_block *dst_blk = | |
195 | (union aegis_block *)dst; | |
196 | const union aegis_block *src_blk = | |
197 | (const union aegis_block *)src; | |
198 | ||
199 | tmp = state->blocks[2]; | |
200 | crypto_aegis_block_and(&tmp, &state->blocks[3]); | |
201 | crypto_aegis_block_xor(&tmp, &state->blocks[5]); | |
202 | crypto_aegis_block_xor(&tmp, &state->blocks[4]); | |
203 | crypto_aegis_block_xor(&tmp, &state->blocks[1]); | |
204 | crypto_aegis_block_xor(&tmp, src_blk); | |
205 | ||
206 | crypto_aegis256_update_a(state, &tmp); | |
207 | ||
208 | *dst_blk = tmp; | |
209 | ||
210 | size -= AEGIS_BLOCK_SIZE; | |
211 | src += AEGIS_BLOCK_SIZE; | |
212 | dst += AEGIS_BLOCK_SIZE; | |
213 | } | |
214 | } else { | |
215 | while (size >= AEGIS_BLOCK_SIZE) { | |
216 | tmp = state->blocks[2]; | |
217 | crypto_aegis_block_and(&tmp, &state->blocks[3]); | |
218 | crypto_aegis_block_xor(&tmp, &state->blocks[5]); | |
219 | crypto_aegis_block_xor(&tmp, &state->blocks[4]); | |
220 | crypto_aegis_block_xor(&tmp, &state->blocks[1]); | |
221 | crypto_xor(tmp.bytes, src, AEGIS_BLOCK_SIZE); | |
222 | ||
223 | crypto_aegis256_update_a(state, &tmp); | |
224 | ||
225 | memcpy(dst, tmp.bytes, AEGIS_BLOCK_SIZE); | |
226 | ||
227 | size -= AEGIS_BLOCK_SIZE; | |
228 | src += AEGIS_BLOCK_SIZE; | |
229 | dst += AEGIS_BLOCK_SIZE; | |
230 | } | |
231 | } | |
232 | ||
233 | if (size > 0) { | |
234 | union aegis_block msg = {}; | |
235 | memcpy(msg.bytes, src, size); | |
236 | ||
237 | tmp = state->blocks[2]; | |
238 | crypto_aegis_block_and(&tmp, &state->blocks[3]); | |
239 | crypto_aegis_block_xor(&tmp, &state->blocks[5]); | |
240 | crypto_aegis_block_xor(&tmp, &state->blocks[4]); | |
241 | crypto_aegis_block_xor(&tmp, &state->blocks[1]); | |
242 | crypto_aegis_block_xor(&msg, &tmp); | |
243 | ||
244 | memset(msg.bytes + size, 0, AEGIS_BLOCK_SIZE - size); | |
245 | ||
246 | crypto_aegis256_update_a(state, &msg); | |
247 | ||
248 | memcpy(dst, msg.bytes, size); | |
249 | } | |
250 | } | |
251 | ||
252 | static void crypto_aegis256_process_ad(struct aegis_state *state, | |
253 | struct scatterlist *sg_src, | |
254 | unsigned int assoclen) | |
255 | { | |
256 | struct scatter_walk walk; | |
257 | union aegis_block buf; | |
258 | unsigned int pos = 0; | |
259 | ||
260 | scatterwalk_start(&walk, sg_src); | |
261 | while (assoclen != 0) { | |
262 | unsigned int size = scatterwalk_clamp(&walk, assoclen); | |
263 | unsigned int left = size; | |
264 | void *mapped = scatterwalk_map(&walk); | |
265 | const u8 *src = (const u8 *)mapped; | |
266 | ||
267 | if (pos + size >= AEGIS_BLOCK_SIZE) { | |
268 | if (pos > 0) { | |
269 | unsigned int fill = AEGIS_BLOCK_SIZE - pos; | |
270 | memcpy(buf.bytes + pos, src, fill); | |
271 | crypto_aegis256_update_a(state, &buf); | |
272 | pos = 0; | |
273 | left -= fill; | |
274 | src += fill; | |
275 | } | |
276 | ||
277 | crypto_aegis256_ad(state, src, left); | |
278 | src += left & ~(AEGIS_BLOCK_SIZE - 1); | |
279 | left &= AEGIS_BLOCK_SIZE - 1; | |
280 | } | |
281 | ||
282 | memcpy(buf.bytes + pos, src, left); | |
283 | ||
284 | pos += left; | |
285 | assoclen -= size; | |
286 | scatterwalk_unmap(mapped); | |
287 | scatterwalk_advance(&walk, size); | |
288 | scatterwalk_done(&walk, 0, assoclen); | |
289 | } | |
290 | ||
291 | if (pos > 0) { | |
292 | memset(buf.bytes + pos, 0, AEGIS_BLOCK_SIZE - pos); | |
293 | crypto_aegis256_update_a(state, &buf); | |
294 | } | |
295 | } | |
296 | ||
297 | static void crypto_aegis256_process_crypt(struct aegis_state *state, | |
298 | struct aead_request *req, | |
299 | const struct aegis256_ops *ops) | |
300 | { | |
301 | struct skcipher_walk walk; | |
f606a88e OM |
302 | |
303 | ops->skcipher_walk_init(&walk, req, false); | |
304 | ||
305 | while (walk.nbytes) { | |
0f533e67 | 306 | unsigned int nbytes = walk.nbytes; |
f606a88e | 307 | |
0f533e67 EB |
308 | if (nbytes < walk.total) |
309 | nbytes = round_down(nbytes, walk.stride); | |
f606a88e | 310 | |
0f533e67 EB |
311 | ops->crypt_chunk(state, walk.dst.virt.addr, walk.src.virt.addr, |
312 | nbytes); | |
313 | ||
314 | skcipher_walk_done(&walk, walk.nbytes - nbytes); | |
f606a88e OM |
315 | } |
316 | } | |
317 | ||
318 | static void crypto_aegis256_final(struct aegis_state *state, | |
319 | union aegis_block *tag_xor, | |
320 | u64 assoclen, u64 cryptlen) | |
321 | { | |
322 | u64 assocbits = assoclen * 8; | |
323 | u64 cryptbits = cryptlen * 8; | |
324 | ||
325 | union aegis_block tmp; | |
326 | unsigned int i; | |
327 | ||
328 | tmp.words64[0] = cpu_to_le64(assocbits); | |
329 | tmp.words64[1] = cpu_to_le64(cryptbits); | |
330 | ||
331 | crypto_aegis_block_xor(&tmp, &state->blocks[3]); | |
332 | ||
333 | for (i = 0; i < 7; i++) | |
334 | crypto_aegis256_update_a(state, &tmp); | |
335 | ||
336 | for (i = 0; i < AEGIS256_STATE_BLOCKS; i++) | |
337 | crypto_aegis_block_xor(tag_xor, &state->blocks[i]); | |
338 | } | |
339 | ||
340 | static int crypto_aegis256_setkey(struct crypto_aead *aead, const u8 *key, | |
341 | unsigned int keylen) | |
342 | { | |
343 | struct aegis_ctx *ctx = crypto_aead_ctx(aead); | |
344 | ||
345 | if (keylen != AEGIS256_KEY_SIZE) { | |
346 | crypto_aead_set_flags(aead, CRYPTO_TFM_RES_BAD_KEY_LEN); | |
347 | return -EINVAL; | |
348 | } | |
349 | ||
350 | memcpy(ctx->key[0].bytes, key, AEGIS_BLOCK_SIZE); | |
351 | memcpy(ctx->key[1].bytes, key + AEGIS_BLOCK_SIZE, | |
352 | AEGIS_BLOCK_SIZE); | |
353 | return 0; | |
354 | } | |
355 | ||
356 | static int crypto_aegis256_setauthsize(struct crypto_aead *tfm, | |
357 | unsigned int authsize) | |
358 | { | |
359 | if (authsize > AEGIS256_MAX_AUTH_SIZE) | |
360 | return -EINVAL; | |
361 | if (authsize < AEGIS256_MIN_AUTH_SIZE) | |
362 | return -EINVAL; | |
363 | return 0; | |
364 | } | |
365 | ||
366 | static void crypto_aegis256_crypt(struct aead_request *req, | |
367 | union aegis_block *tag_xor, | |
368 | unsigned int cryptlen, | |
369 | const struct aegis256_ops *ops) | |
370 | { | |
371 | struct crypto_aead *tfm = crypto_aead_reqtfm(req); | |
372 | struct aegis_ctx *ctx = crypto_aead_ctx(tfm); | |
373 | struct aegis_state state; | |
374 | ||
375 | crypto_aegis256_init(&state, ctx->key, req->iv); | |
376 | crypto_aegis256_process_ad(&state, req->src, req->assoclen); | |
377 | crypto_aegis256_process_crypt(&state, req, ops); | |
378 | crypto_aegis256_final(&state, tag_xor, req->assoclen, cryptlen); | |
379 | } | |
380 | ||
381 | static int crypto_aegis256_encrypt(struct aead_request *req) | |
382 | { | |
383 | static const struct aegis256_ops ops = { | |
384 | .skcipher_walk_init = skcipher_walk_aead_encrypt, | |
385 | .crypt_chunk = crypto_aegis256_encrypt_chunk, | |
386 | }; | |
387 | ||
388 | struct crypto_aead *tfm = crypto_aead_reqtfm(req); | |
389 | union aegis_block tag = {}; | |
390 | unsigned int authsize = crypto_aead_authsize(tfm); | |
391 | unsigned int cryptlen = req->cryptlen; | |
392 | ||
393 | crypto_aegis256_crypt(req, &tag, cryptlen, &ops); | |
394 | ||
395 | scatterwalk_map_and_copy(tag.bytes, req->dst, req->assoclen + cryptlen, | |
396 | authsize, 1); | |
397 | return 0; | |
398 | } | |
399 | ||
400 | static int crypto_aegis256_decrypt(struct aead_request *req) | |
401 | { | |
402 | static const struct aegis256_ops ops = { | |
403 | .skcipher_walk_init = skcipher_walk_aead_decrypt, | |
404 | .crypt_chunk = crypto_aegis256_decrypt_chunk, | |
405 | }; | |
406 | static const u8 zeros[AEGIS256_MAX_AUTH_SIZE] = {}; | |
407 | ||
408 | struct crypto_aead *tfm = crypto_aead_reqtfm(req); | |
409 | union aegis_block tag; | |
410 | unsigned int authsize = crypto_aead_authsize(tfm); | |
411 | unsigned int cryptlen = req->cryptlen - authsize; | |
412 | ||
413 | scatterwalk_map_and_copy(tag.bytes, req->src, req->assoclen + cryptlen, | |
414 | authsize, 0); | |
415 | ||
416 | crypto_aegis256_crypt(req, &tag, cryptlen, &ops); | |
417 | ||
418 | return crypto_memneq(tag.bytes, zeros, authsize) ? -EBADMSG : 0; | |
419 | } | |
420 | ||
421 | static int crypto_aegis256_init_tfm(struct crypto_aead *tfm) | |
422 | { | |
423 | return 0; | |
424 | } | |
425 | ||
426 | static void crypto_aegis256_exit_tfm(struct crypto_aead *tfm) | |
427 | { | |
428 | } | |
429 | ||
430 | static struct aead_alg crypto_aegis256_alg = { | |
431 | .setkey = crypto_aegis256_setkey, | |
432 | .setauthsize = crypto_aegis256_setauthsize, | |
433 | .encrypt = crypto_aegis256_encrypt, | |
434 | .decrypt = crypto_aegis256_decrypt, | |
435 | .init = crypto_aegis256_init_tfm, | |
436 | .exit = crypto_aegis256_exit_tfm, | |
437 | ||
438 | .ivsize = AEGIS256_NONCE_SIZE, | |
439 | .maxauthsize = AEGIS256_MAX_AUTH_SIZE, | |
440 | .chunksize = AEGIS_BLOCK_SIZE, | |
441 | ||
442 | .base = { | |
f606a88e OM |
443 | .cra_blocksize = 1, |
444 | .cra_ctxsize = sizeof(struct aegis_ctx), | |
445 | .cra_alignmask = 0, | |
446 | ||
447 | .cra_priority = 100, | |
448 | ||
449 | .cra_name = "aegis256", | |
450 | .cra_driver_name = "aegis256-generic", | |
451 | ||
452 | .cra_module = THIS_MODULE, | |
453 | } | |
454 | }; | |
455 | ||
456 | static int __init crypto_aegis256_module_init(void) | |
457 | { | |
458 | return crypto_register_aead(&crypto_aegis256_alg); | |
459 | } | |
460 | ||
461 | static void __exit crypto_aegis256_module_exit(void) | |
462 | { | |
463 | crypto_unregister_aead(&crypto_aegis256_alg); | |
464 | } | |
465 | ||
466 | module_init(crypto_aegis256_module_init); | |
467 | module_exit(crypto_aegis256_module_exit); | |
468 | ||
469 | MODULE_LICENSE("GPL"); | |
470 | MODULE_AUTHOR("Ondrej Mosnacek <omosnacek@gmail.com>"); | |
471 | MODULE_DESCRIPTION("AEGIS-256 AEAD algorithm"); | |
472 | MODULE_ALIAS_CRYPTO("aegis256"); | |
473 | MODULE_ALIAS_CRYPTO("aegis256-generic"); |